Project Summary ? Virology Core (Rice) Development of a vaccine capable of eliciting a robust neutralizing antibody response against Zika virus (ZIKV) while minimizing possible non-neutralizing antibodies that could cause enhancement of related flaviviruses such as dengue virus (DENV) will require an in-depth understanding of antibodies with potently neutralization capacity. Focusing on the ZIKV envelope protein (E) we will utilize a process of antibody discovery from ZIKV exposed individuals, structural characterization of the neutralizing antibody ? E epitope interaction, and design and testing of epitope-specific immunogens for antibody elicitation and protection from ZIKV infection in a small animal model. This will require assays for assessing the ability of antibodies to neutralize ZIKV and the related DENV, as well as their potential to cause antibody-dependent enhancement of infection of these related viruses. The Virology Core will generate luciferase-expressing reporter viral particles (RVPs) and characterized virus stocks for ZIKV, and the four serotypes of DENV to facilitate the studies. Using cloned and recombinantly expressed antibodies or sera from immunized mice (Project 1), the Virology Core will perform high throughput assays to elucidate the neutralization and enhancement capacity. Confirmatory detailed studies on samples of interest will be conducted with live virus. Live virus will also be utilized in challenge and enhancement studies after vaccination in the murine model (Project 1) and for structural studies of select antibodies bound to the virus particle (Project 2). Based on structural and biochemical studies of the antibody ? epitope interaction (Project 2), RVPs coated with ZIKV proteins containing specific mutations in E will be generated by the Virology Core and used to test the epitope requirements for neutralization or enhancement. The resulting information will inform immunogen design and testing (Projects 2 and 1) for experiments to elicit specific neutralizing antibody responses. The need for a large number of quality controlled viral stocks and RVPs representing ZIKV, the four serotypes of DENV, as well as epitope mutants requires a dedicated Virology Core.